Rotary hydraulic machines

ABSTRACT

A rotary hydraulic machine includes a rotor with first and second rows of radial pistons therein. The rotor is journalled on a pintle which has two pairs of ports, with each pair being associated with a respective row of pistons. The pistons in the first row have a larger displacement per revolution of the rotor than the pistons in the second row. One of the ports associated with the first row communicates with an inlet and one of the ports associated with the second row communicates with an outlet for the machine. Pressurized fluid supplied to the inlet causes the pistons in the first row to act as a motor driving the pistons in the second row to act as a pump.

, United States Patent 11 1 [111 3,806,281 Skinner 1 Apr. 23, 1974 [54] ROTARY HYDRAULIC MACHINES 3,241,463 3/1966 Barrett 91/493 3,579,985 5/1971 Barrett..... 91/492 [761 Inventor: fl Tlwmas Johhskmhe" 36 2,935,952 5/1960 Rose 417/225 Hermflage Way, Kemlworlh, 3,188,963 6/1965 Tyler 417/225 Warwickshire, England 22 an. 7 1972 Primary Examiner-Williarn L. Freeh 1 l 6 J Assistant Examiner-Gregory LaPointe [21] Appl- No. 2 Attorney, Agent, or Firm-Holman & Stern [30] Foreign Application Priority Data [57] ABSTRACT Jan. 7, 1971 Great Britain 746/71 A Mary hydraulic machine includes with first and second rows of radial pistons therein. The rotor is 52 us. 01. 417/225, 417/391 ioumalled on a P which has two Pairs of Ports, [51] Int. Cl. F04b 35/02 with each pair being associated with a respective row 58 Field 61 Search 417/342, .343, 344, 345, O Pistons The PistonS in first row have a larger 417/346, 347, 225, 391, 244, 226, 227, 287; displacement per revolution of the rotor than the pis- 91/492 60/53 13, 494 tons in thesecond row. One of the ports associated with the first row'coi'nmunicates with an inlet and one [56] References Cited of the ports associated with the second row communicates with an outlet for the machine. Pressurized fluid UNITED STATES PATENTS supplied to the inlet causes the pistons in the first row j at to act as a motor driving the pistons in the second row 0y p 1 3,194,225 7/1965 Kemp 417/225 act pump 2,872,875 2/1959 Mergen et al., 91/492 1 Claim, 5 Drawing [Figures 1 v y 21 EO' 4 4- E2 7 J l l t; IE 41 1 ROTARY HYDRAULIC MACHINES BACKGROUND OF THE INVENTION pistons slidable in the bores, a pair of cam rings surrounding the rotor within the casing and disposed eccentrically of the rotor, inside surfaces of the rings being engaged by pistons in the respective rows and the arrangement being such that, in use, the pistons in the first row have a larger displacement per revolution of the rotor than the pistons in the second row, two pairs of ports in the pintle, the bores in the respective rows successively communicating, in use, with the ports of a respective pair, an inlet for the machine communicating with one of the ports of a first pair which communicatewith the bores ofsaid first row, a first outlet for the machine communicating with one of a second ports of the pair thereof which communicate with the bores of,

said second row, a passage connecting a port in one of the pairs to aport in the other of the pairs and a second outlet through which is discharged, in use, fluid which is not discharged through the first outlet.

Embodiments of the invention will now be described by way of exampleand with reference to the accompa nying drawings in which:

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a section through a hydraulic machine,

FIG. 2 is a section on line 22 in FIG. 1,

FIG. 3 is a section on line 33 in FIG. 1, and with parts removed for clarity,

FIG. 4 is a fragmentary view corresponding to FIG. 3, of an alternative form of machine, and

FIG. Sis a similar scrap view of a further alternative form of machine.

DETAILED DESCRIPTION OF THE INVENTION Considering first the embodiments shown in FIGS. 1 to 3, a machine has acasing formed in two parts 11, 12. Part 12 includes a pintle 13 extending axially into the casing 10. Mounted on the pintle 13 is a rotor 14 which has two axially spaced rows 15, 16 of radial bores, there being an equal number of bores in each row and the bores in row being aligned with the bores in row 16. Slidable within the bores are pistons 17. Surrounding the rotor 14 are cam rings l8, 19 whose inner faces are engaged by the pistons in the respective rows 15, 16.

' The cam rings 18, 19 are mounted in support rings Cam rings 18,19 are movable to desired amounts of eccentricity with respect to the rotor 14 by means of pairs of screws 23,24 which respectively engage the support rings 20, 21. I

Within the pintle 13 is an arrangement of ports which is shown in greater detail in FIG. 3, from which the rotor 14 and cam rings 18,19 have been omitted for clarity. A first pair of ports 25, 26 are arranged on op- 20, 21 respectively by means of needle roller bearings posite sides of the pintle 13 so as successively to cornmunicate, in use, with the bores of the row 15. A further pair of ports 27, 28 is similarly arranged to communicate with the bores of the row 16. An inlet 29 for the machine in casing part communicates with port 25 via a passage 30. An outlet 31 for the machine in casing part 12 communicates with port 27 via a passage 32. Ports 26, 28 communicate with each other and with a spring loaded relief valve 33 in casing part 11 viaa passage 34. The relief valve communicates on its downstream side with the inside of the casing 10. A drain outlet 35 opens into the casing 10 through the part 12.

In use, a fluid under pressure is supplied to inlet 29 v and acts in a known manner on the pistons 17 in row 15 to drive the rotor 14, with the fluid being discharged via port 26 and passage 34 into port 28. The pistons of row 16 act as a pump to deliver the fluid via port 27 to the outlet 31. It is arranged that the eccentricity of the cam ring 19 is less than that of cam ring 18. The volume swept per revolution by the pistons 17 in row 16 is thus less than that swept by the pistons in row 15. Fluid is thus delivered to the outlet 31 at a higher pressure than that at the inlet 29. An amount of fluid equal to the difference in displacement between the motor and the pump escapes via the relief valve33 and the. drain out let 35. The pressure at which valve 33 operates is sufficient to ensure that even at very low rotor speeds, the pistons 17 are maintained in contact with their associated carn rings.

FIG. 4 shows a pintle 40 for an alternative form of machine according to theinvention. Pintle 40 has ports 25, 26, 27 and 28 as above described. Ports 25, 27 communicate, also as described, with inlet 29 and out let 31 respectively. Port26 communicates, via relief valve 33 with the inside of casing 1.0. Port 28 communicates, however, with port 25 instead of with port 26. The motor and pump portions of the machine are thus connected in parallel to the inlet 29, withall fluid passing through the motor being discharged to a drain via relief valve 33. Fluid passing through the pump portion is discharged via outlet 31, as, before. i

FIG. 5 shows a pintle '41 for yet another alternative form of machine. Pintle 41 also has ports 25,26, 27, and 28. Port 25' communicates with inlet 29 as before and port 26 communicates via relief valve 33 with the inside of casing 10. Port 27, however, communicates with inlet 29 and port 25. Port 28 communicates with outlet 31, from which, in use, fluid is delivered at high pressure.

The pump and motor portions are thereby, once again, connected in parallel, with the ports 25, 27 respectively forming the inlet ports. In this arrangement the cam rings 18, 19 are arranged so that their eccentricities with respect to the rotor are both on the same side of the latter.

I claim:

1. A rotary hydraulic machine comprising a-casing, a pintle within the casing, a rotor mounted on the pintle, first and second axially spaced rows of radial bores;

4 thereof which communicates with thebores of said second row, a passage connecting the other port of each pair, a spring loaded relief valve for said passage communicating on its downstream side with the casing interior and a second outlet communicating with the casing interior and through which is discharged, in use, fluid which is not discharged through the first outlet via the pistons in the second row 

1. A rotary hydraulic machine comprising a casing, a pintle within the casing, a rotor mounted on the pintle, first and second axially spaced rows of radial bores in the rotor, a plurality of pistons slidable in the radial bores constituting a motor and a pump respectively, a pair of cam rings surrounding the rotor within the casing and disposed eccentrically of the rotor, said rings having inside surfaces engaged by the pistons in the respective rows and the arrangement being such that, in use, the pistons in the first row constituting the motor have a larger displacement per revolution of the rotor than The pistons in the second row constituting the pump, two pairs of opposed ports in the pintle, the bores in the respective row successively communicating, in use, with the ports of a respective pair, an inlet for the machine communicating with one of the ports of a first pair thereof which communicates with the bores of said first row, a first outlet for the machine communicating with one of the ports of a second pair thereof which communicates with the bores of said second row, a passage connecting the other port of each pair, a spring loaded relief valve for said passage communicating on its downstream side with the casing interior and a second outlet communicating with the casing interior and through which is discharged, in use, fluid which is not discharged through the first outlet via the pistons in the second row. 